Various foods, glass products such as lenses, leather products such as leather boots, leather jumpers and fur coats and products of paints and pastes formed of starch or cellulose are apt to mold. This considerably reduces validity of the goods or calls for waste disposal thereof.
Apart from mold, increased growth of harmful microorganisms, too, considerably reduces validity of the goods or demands for waste disposal thereof. For example, in the case of foods, there are caused problems of fermentation and food poisoning due to increased growth of bacteria.
It is known to seal-pack an article together with an oxygen absorber with a packing material and to maintain the oxygen concentration within the pack below 1 or less for the purpose of preventing the article from molding. While this method can effectively prevent generation of mold by aerobic bacteria, this cannot be an effective means for preventing increase and growth of anaerobic bacteria which account for food poisoning or fermentation.
It is also known to seal-pack an article together with an ethanol-emanating agent and to fill the inside of the pack with ethanol vapors for the purpose of preventing the formation of mold and the growth of ordinary bacteria. With this method, .satisfactory effect cannot be obtained unless ethanol which is expensive is used in a relatively large amount.
Further, a number of mildew-proofing agents and anti-bacterial agents are hitherto known. Most of these chemicals, however, have toxicity to human bodies so that the use thereof is subjected to severe restriction.
A number of natural products having an antimicrobial action are hitherto known. Especially, Eutrema wasabi is known to have an excellent germicidal activity. It is also known to subject food to a germ-destroying treatment using an isothiocyanate (hereinafter referred to simply as ISOTC) which is a major component of wasabi. For example, Japanese Published Unexamined Patent Application No. Sho-57-99182 discloses an aqueous emulsion composition obtained by emulsion-dispersing, in water in the presence of an emulsifier, a solution of ISOTC dissolved in an oil. This aqueous emulsion composition is used by mixing into a food so as to sterilizing the food. However, the incorporation of such an aqueous emulsion into foods is not preferable not only because taste of the foods deteriorates but also because ISOTC in foods is apt to decompose. Japanese Published Unexamined Patent Application No. Sho-58-63348 discloses a method for preserving vegetables and fruits wherein the vegetables and fruits are packed in a packaging vessel together with a synthetic zeolite which has a pore diameter of 5-10.ANG. and which is impregnated with ISOTC in a proportion of about 5% by weight. The ISOTC-impregnated zeolite does not emanate an effective amount of ISOTC vapors in air. It can adsorb moisture in air when subjected to a high humidity condition of a relative humidity of 90% or more with the simultaneous generation of ISOTC adsorbed therein. This known method has problems because the synthetic zeolite with a pore diameter of 5-10.ANG. to be used as an absorbent of ISOTC is expensive and because the amount of ISOTC adsorbed thereto is very low of about 5% by weight. The known, ISOTC-absorbed, synthetic zeolite has also a drawback because it cannot emanate ISOTC vapors unless it is subjected to a high humidity condition. Thus, the ISOTC-adsorbed, synthetic zeolite is not effectively utilized as a general ISOTC vapor-generating agent.
As described in the foregoing, several techniques for destroying germs with the use of ISOTC which is a major ingredient of wasabi are known. However, none of them are satisfactory from the practical standpoint.
With attention paid to the fact that the ISOTC as one of major ingredients for wasabi is an oily substance, the present inventors have succeeded in dissolving the ISOTC in a particular oily substance and providing a germicidal composition in a liquid form having an irritating odor controlled to an extremely low level and easy to handle by controlling the concentration of the ISOTC in the liquid form.
The present inventors have previously provided a germicidal composition in a solid form capable of generating the ISOTC vapor by having such an oily germicidal agent contained in a variety of solid materials.
Further, the present inventors have succeeded in providing various germicidal products by having the germicidal composition contained in the various products.
Furthermore, the present inventors have provided methods or processes for gem-destroying articles with the ISOTC vapor and apparatuses to be employed therefor.
Therefore, the present invention has the major object to improve and enlarge the technology for the gem-destroying treatment using the ISOTC.
The present invention has another object to provide a process for preparing germ-free air.
The present invention has a further object to provide a process for preparing germ-free water.
The present invention has a still further object to provide a process for processing food, which contains the gem-destroying treatment.
The present invention has a still further object to provide a process for boiling cereals thereby producing germ-free food products.
The present invention has still further objects to provide a fumigant and a process for fumigation.
The present invention has still further objects to provide various products having germicidal action and a process for producing the same.
The present invention has another still further objects to provide germicidal gas compositions, a process for preparing the germicidal gas compositions, and an apparatus for use with the process therefor.
As a result of extensive research and studies with the attempt to achieve the aforesaid objects, it has been found that the germ-free air can be prepared by admixing the air with the ISOTC vapor to thereby destroy or kill harmful microorganisms contained in the air and removing the ISOTC from the air.
It is also found that the gem-free water can be prepared by admixing the water with the ISOTC vapor to thereby destroy or kill harmful microorganisms contained in the water and removing the ISOTC from the water.
It is further found that the germ-free, processed food can be prepared by processing food in contact with the ISOTC.
It is further found that the germ-free, heat-treated cereals can be prepared by destroying germs on the cereals in contact with the ISOTC and boiling them.
It is still further found that an odor originating from the ISOTC can be removed by admixing the ISOTC vapor with a fragrant ingredient, in bringing the food into contact with the ISOTC vapor.
It is still further found that allyl isothiocyanate among the ISOTC can demonstrate excellent fumigating action.
It is still further found that germicidal products can be prepared by bringing various products or articles into contact with gases containing the ISOTC vapor.
It is still further found that the germicidal gas composition can be prepared by bubbling gases into a mixture of a liquid of the ISOTC or a solution thereof with an organic liquid.